This invention relates to a pressure regulator for harsh environment service and also relates to a method of maintaining a desired back pressure on a variable flow gas stream.
In many continuous chemical or metallurgical processes where reactions are carried out in pressurized flow reactors--reactors in which a gas flows in to and out of a reactor vessel within which it takes part in a chemical reaction--it is desirable to maintain the reactor vessel at a controlled pressure. This is usually accomplished by a control valve which imposes a variable area flow restriction in the exit gas line. However, control valves generally have narrow ranges of pressure or flow over which control is precise. In addition when high temperatures and/or entrained particulates and/or corrosive constituents occur in the exit gas stream, and also when the gas flow from the reactor fluctuates greatly with time, the control valves malfunction rendering them unreliable and perhaps rendering the process system potentially unsafe. Control valves are subject, for example, to binding, corrosion, erosion, plugging and fouling. This is especially true in experimental pilot plant work.
Thus a method and apparatus are needed for controlling the pressure within a flow reactor operated under harsh environmental conditions which is effective with highly fluctuating flow rates and over wide ranges of pressure and which does not suffer from the disadvantages of a variable orifice control valve.